U.S. patent application number 16/194041 was filed with the patent office on 2020-05-21 for methods for forming a metal silicate film on a substrate in a reaction chamber and related semiconductor device structures.
The applicant listed for this patent is ASM IP Holding B.V.. Invention is credited to Michael Eugene Givens, Peng-Fu Hsu, Fu Tang, Qi Xie.
Application Number | 20200161438 16/194041 |
Document ID | / |
Family ID | 70728372 |
Filed Date | 2020-05-21 |
United States Patent
Application |
20200161438 |
Kind Code |
A1 |
Tang; Fu ; et al. |
May 21, 2020 |
METHODS FOR FORMING A METAL SILICATE FILM ON A SUBSTRATE IN A
REACTION CHAMBER AND RELATED SEMICONDUCTOR DEVICE STRUCTURES
Abstract
Methods for forming a metal silicate film on a substrate in a
reaction chamber by a cyclical deposition process are provided. The
methods may include: regulating the temperature of a hydrogen
peroxide precursor below a temperature of 70.degree. C. prior to
introduction into the reaction chamber, and depositing the metal
silicate film on the substrate by performing at least one unit
deposition cycle of a cyclical deposition process. Semiconductor
device structures including a metal silicate film formed by the
methods of the disclosure are also provided.
Inventors: |
Tang; Fu; (Phoenix, AZ)
; Hsu; Peng-Fu; (Scottsdale, AZ) ; Givens; Michael
Eugene; (Scottsdale, AZ) ; Xie; Qi; (Leuven,
BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASM IP Holding B.V. |
Almere |
|
NL |
|
|
Family ID: |
70728372 |
Appl. No.: |
16/194041 |
Filed: |
November 16, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/02145 20130101;
H01L 21/02205 20130101; C23C 16/403 20130101; H01L 29/66477
20130101; H01L 21/2807 20130101; H01L 29/78 20130101; H01L 29/161
20130101; H01L 21/28158 20130101; H01L 29/408 20130101; C23C 16/401
20130101; H01L 29/517 20130101; H01L 21/0228 20130101; H01L 21/022
20130101; H01L 29/513 20130101 |
International
Class: |
H01L 29/40 20060101
H01L029/40; H01L 21/02 20060101 H01L021/02; H01L 21/28 20060101
H01L021/28; H01L 29/66 20060101 H01L029/66; H01L 29/161 20060101
H01L029/161; H01L 29/51 20060101 H01L029/51; H01L 29/78 20060101
H01L029/78; C23C 16/40 20060101 C23C016/40 |
Claims
1. A method for forming a metal silicate film on a substrate in a
reaction chamber by a cyclical deposition process, the method
comprising: regulating the temperature of a hydrogen peroxide
precursor below a temperature of 70.degree. C. prior to
introduction into the reaction chamber; and depositing the metal
silicate film on the substrate by performing at least one unit
deposition cycle of a cyclical deposition process, wherein a unit
deposition cycle comprises: contacting the substrate with a metal
vapor phase precursor; contacting the substrate with a silicon
vapor phase precursor; and contacting the substrate with the
hydrogen peroxide precursor.
2. The method of claim 1, wherein the hydrogen peroxide precursor
decomposes proximate to the substrate.
3. The method of claim 1, wherein the reaction chamber comprises a
showerhead reactor utilizing a showerhead gas distribution
mechanism to introduce the metal vapor phase precursor, the silicon
vapor phase precursor, and the hydrogen peroxide precursor into the
reaction chamber and the method further comprises regulating the
temperature of the showerhead gas distribution mechanism to a
temperature below 70.degree. C.
4. The method of claim 1, further comprising regulating the
temperature of at least one chamber wall of the reaction chamber at
least at those portion of the at least one chamber wall exposed to
the metal vapor phase precursor, the silicon vapor phase precursor,
and the hydrogen precursor, to a temperature below 70.degree.
C.
5. The method of claim 1, wherein the metal vapor phase precursor
comprises at least one of: a hafnium precursor, an yttrium
precursor, a zirconium precursor, an aluminum precursor, a scandium
precursor, a cerium precursor, an erbium precursor, or a strontium
precursor.
6. The method of claim 5, wherein the aluminum precursor comprises
at least one of: trimethylaluminum (TMA), triethylaluminum (TEA),
aluminum trichloride (AlCl.sub.3), dimethyaluminum hydride (DMAH),
or dimethylaluminum isopropoxide (DMAI).
7. The method of claim 1, wherein the metal silicate film comprises
an aluminum silicate film (Al.sub.xSi.sub.yO.sub.z) with an atomic
percentage of silicon between approximately 10 atomic-% and
approximately 60 atomic-%.
8. The method of claim 7, wherein the metal silicate film comprises
an aluminum silicate film (Al.sub.xSi.sub.yO.sub.z) with an atomic
percentage of silicon between approximately 10 atomic-% and
approximately 30 atomic-%.
9. The method of claim 1, wherein the metal silicate film comprises
an aluminum silicate film (Al.sub.xSi.sub.yO.sub.z) with an atomic
percentage of silicon less than 10 atomic-%.
10. The method of claim 1, wherein the silicon vapor phase reactant
comprises at least one of: silanediamine N,N,N',N-tetraethyl
(C.sub.8H.sub.22N.sub.2Si), BTBAS (bis(tertiarybutylamino)silane),
BDEAS (bis(diethylamino)silane), TDMAS (tris(dimethylamino)silane),
hexakis(ethylamino)disilane (Si.sub.2(NHC.sub.2H.sub.5).sub.6),
silicon tetraiodide (Si.sub.4), silicon tetrachloride (SiCl.sub.4),
hexachlorodisilane (HCDS), pentachlorodisilane(PCDS), a silane, an
aminosilane, or a silicon halide.
11. The method of claim 1, wherein the metal silicate film is
deposited on the substrate without an incubation period.
12. The method of claim 1, wherein the substrate comprises a
plurality of channel regions and the metal silicate film is
deposited directly on the plurality of channel regions.
13. The method of claim 12, further comprising passivating a
surface of the plurality of channel regions prior to deposition of
the metal silicate film, wherein passivating the surface comprises
exposing the surface of the plurality of channel regions to a
gas-phase sulfur precursor.
14. The method of claim 13, wherein the gas-phase sulfur precursor
comprises at least one of (NH.sub.4).sub.2S, H.sub.2S, NH.sub.4HS,
or an organosulfur compound.
15. The method of claim 12, further comprising depositing a high-k
dielectric material directly on the metal silicate film, such that
the metal silicate film forms an interface layer disposed directly
between the plurality of channel regions and the high-k dielectric
material.
16. The method of claim 13, wherein the interface trap density at
an interface between the plurality of channel regions and the metal
silicate film is less than about 7 e.sup.11 cm.sup.-2 eV.sup.-1 for
mid-gap states.
17. The method of claim 12, wherein the metal silicate film has an
effective oxide charge density of less than 5 e.sup.10
cm.sup.-2.
18. The method of claim 12, wherein the plurality of channel
regions comprises silicon germanium (Si.sub.1-xGe.sub.x) wherein x
is between 0 and approximately 0.50.
19. A semiconductor processing apparatus configured for performing
the method of claim 1.
20. A semiconductor device structure comprising: a silicon
germanium (Si.sub.1-xGe.sub.x) channel region; an interface layer
comprising an aluminum silicate film disposed directly on the
silicon germanium (Si.sub.1-xGe.sub.x) channel region; and a high-k
dielectric material disposed directly on the interface layer;
wherein an interface trap density at an interface between the
silicon germanium (Si.sub.1-xGe.sub.x) channel region and the
interface layer is less than about 7 e.sup.11 cm.sup.-2 eV.sup.-1
for mid-gap states.
21-27. (canceled)
Description
FIELD OF INVENTION
[0001] The present disclosure relates generally to methods for
forming a metal silicate film on a substrate in a reaction chamber
by a cyclical deposition process and in particular to methods for
forming a metal silicate film utilizing a hydrogen peroxide
precursor as the oxidizing agent precursor. The present disclosure
is also related generally to semiconductor device structures
comprising a metal silicate film deposited by a cyclical deposition
process.
BACKGROUND OF THE DISCLOSURE
[0002] Metal silicate films, such as, for example, hafnium silicate
films (Hf.sub.xSi.sub.yO.sub.z), ytrrium silicate films
(Y.sub.xSi.sub.yO.sub.z), zirconium silicate films
(ZrxSi.sub.yO.sub.z), or aluminum silicate films
(Al.sub.xSi.sub.yO.sub.z), may be utilized for variety of different
applications in the field of semiconductor device technologies. As
an example, metal silicate films may be used to replace silicon
oxide in some applications, such as complementary metal oxide
semiconductor (CMOS) applications, because the metal silicate films
can offer excellent thermal stability and device performance in
semiconductor device structures.
[0003] Cyclical deposition processes, such as, for example, atomic
layer deposition (ALD) and cyclical chemical vapor deposition
(CCVD), sequentially introduce two or more precursors (reactants)
into a reaction chamber wherein the precursors react with the
surface of the substrate one at a time in a sequential manner.
Cyclical deposition processes have been demonstrated which produce
metal silicate films with excellent conformality with atomic level
thickness control.
[0004] Cyclical deposition processes employed to deposit metal
silicate films commonly utilize water (H.sub.2O) as the oxidizing
agent precursor. However, due to the limited reactivity of water
(H.sub.2O), an alternative oxidizing agent precursor is desirable.
Accordingly, methods for forming metal silicate films and related
semiconductor device structures including metal silicate films are
desirable which utilize an oxidizing agent precursor with enhanced
reactivity when compared with common water (H.sub.2O) based
cyclical deposition processes.
SUMMARY OF THE DISCLOSURE
[0005] This summary is provided to introduce a selection of
concepts in a simplified form. These concepts are described in
further detail in the detailed description of example embodiments
of the disclosure below. This summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used to limit the scope of the claimed
subject matter.
[0006] In some embodiments, methods of forming a metal silicate
film on a substrate in a reaction chamber by a cyclical deposition
process are provided. The methods may comprise: regulating the
temperature of a hydrogen peroxide precursor below a temperature of
70.degree. C. prior to introduction into the reaction chamber; and
depositing the metal silicate film on the substrate by performing
at least one unit deposition cycle of a cyclical deposition
process, wherein a unit deposition cycle comprises: contacting the
substrate with a metal vapor phase precursor, contacting the
substrate with a silicon vapor phase precursor; and contacting the
substrate with the hydrogen peroxide precursor.
[0007] In some embodiments, semiconductor device structures are
also provided. The semiconductor device structures may comprise: a
silicon germanium (Si.sub.1-xGe.sub.x) channel region; an interface
layer comprising an aluminum silicate film disposed directly on the
silicon germanium (Si.sub.1-xGe.sub.x) channel region; and a high-k
dielectric material disposed directly on the interface layer;
wherein an interface trap density at an interface between the
silicon germanium (Si.sub.1-xGe.sub.x) channel region and the
interface layer is less than about 7 e.sup.11 cm.sup.-2 eV.sup.-1
for mid-gap states.
[0008] For purposes of summarizing the invention and the advantages
achieved over the prior art, certain objects and advantages of the
invention have been described herein above. Of course, it is to be
understood that not necessarily all such objects or advantages may
be achieved in accordance with any particular embodiment of the
invention. Thus, for example, those skilled in the art will
recognize that the invention may be embodied or carried out in a
manner that achieves or optimizes one advantage or group of
advantages as taught or suggested herein without necessarily
achieving other objects or advantages as may be taught or suggested
herein.
[0009] All of these embodiments are intended to be within the scope
of the invention herein disclosed. These and other embodiments will
become readily apparent to those skilled in the art from the
following detailed description of certain embodiments having
reference to the attached figures, the invention not being limited
to any particular embodiment(s) disclosed.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0010] While the specification concludes with claims particularly
pointing out and distinctly claiming what are regarded as
embodiments of the invention, the advantages of embodiments of the
disclosure may be more readily ascertained from the description of
certain examples of the embodiments of the disclosure when read in
conjunction with the accompanying drawings, in which:
[0011] FIG. 1 illustrates a non-limiting exemplary process flow for
forming a metal silicate film according to the embodiments of the
disclosure;
[0012] FIG. 2 illustrates a non-limiting exemplary semiconductor
device structure including a metal silicate film formed according
to the embodiments of the disclosure; and
[0013] FIG. 3 illustrates a non-limiting exemplary semiconductor
processing apparatus which may be utilized to form a metal silicate
film according to the embodiments of the disclosure.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0014] Although certain embodiments and examples are disclosed
below, it will be understood by those in the art that the invention
extends beyond the specifically disclosed embodiments and/or uses
of the invention and obvious modifications and equivalents thereof.
Thus, it is intended that the scope of the invention disclosed
should not be limited by the particular disclosed embodiments
described below.
[0015] The illustrations presented herein are not meant to be
actual views of any particular material, structure, or device, but
are merely idealized representations that are used to describe
embodiments of the disclosure.
[0016] As used herein, the term "cyclic deposition" may refer to
the sequential introduction of precursors (reactants) into a
reaction chamber to deposit a film over a substrate and includes
deposition techniques such as atomic layer deposition and cyclical
chemical vapor deposition.
[0017] As used herein, the term "cyclical chemical vapor
deposition" may refer to any process wherein a substrate is
sequentially exposed to two or more volatile precursors, which
react and/or decompose on a substrate to produce a desired
deposition.
[0018] As used herein, the term "substrate" may refer to any
underlying material or materials that may be used, or upon which, a
device, a circuit, or a film may be formed.
[0019] As used herein, the term "atomic layer deposition" (ALD) may
refer to a vapor deposition process in which deposition cycles,
preferably a plurality of consecutive deposition cycles, are
conducted in a reaction chamber. Typically, during each cycle the
precursor is chemisorbed to a deposition surface (e.g., a substrate
surface or a previously deposited underlying surface such as
material from a previous ALD cycle), forming a monolayer or
sub-monolayer that does not readily react with additional precursor
(i.e., a self-limiting reaction). Thereafter, if necessary, a
reactant (e.g., another precursor or reaction gas) may subsequently
be introduced into the process chamber for use in converting the
chemisorbed precursor to the desired material on the deposition
surface. Typically, this reactant is capable of further reaction
with the precursor. Further, purging steps may also be utilized
during each cycle to remove excess precursor from the process
chamber and/or remove excess reactant and/or reaction byproducts
from the process chamber after conversion of the chemisorbed
precursor. Further, the term "atomic layer deposition," as used
herein, is also meant to include processes designated by related
terms, such as chemical vapor atomic layer deposition, atomic layer
epitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE, or
organometallic MBE, and chemical beam epitaxy when performed with
alternating pulses of precursor composition(s), reactive gas, and
purge (e.g., inert carrier) gas.
[0020] As used herein, the term "film" may refer to any continuous
or non-continuous structures, material, or materials, deposited by
the methods disclosed herein. For example, a "film" could include
2D materials, nanorods, nanotubes, nanolaminates, or nanoparticles
or even partial or full molecular layers or partial or full atomic
layers or clusters of atoms and/or molecules. A "film" may comprise
material(s) or layer(s) with pinholes, but still be at least
partially continuous.
[0021] As used herein, the term "metal silicate film" may refer to
any film including a metal component, a silicon component, and an
oxygen component, and may have the general formula
M.sub.xSi.sub.yO.sub.z wherein M is the metal component, Si is the
silicon component, O is the oxygen component, and x, y and z
represent the composition of the metal silicate film.
[0022] As used herein, the term "incubation period" may refer to
the number of cyclical deposition cycles in the initial stages of a
cyclical deposition in which no discernable deposition is
observed.
[0023] A number of example materials are given throughout the
embodiments of the current disclosure, it should be noted that the
chemical formulas given for each of the example materials should
not be construed as limiting and that the non-limiting example
materials given should not be limited by a given example
stoichiometry.
[0024] The present disclosure includes methods that may be employed
for forming a high quality, conformal, metal silicate film. The
methods of the current disclosure may employ a cyclical deposition
process that utilizes a hydrogen peroxide precursor as the
oxidizing agent precursor for the deposition of the metal silicate
film. In addition, the temperature of the hydrogen peroxide
precursor may be carefully regulated prior to entry into the
reaction chamber to prevent premature decomposition of the hydrogen
peroxide precursor.
[0025] Common cyclical deposition processes for forming metal
silicate films have regularly employed water (H.sub.2O) as the
oxygen precursor. However, even though water (H.sub.2O) is the most
studied and employed oxygen precursor for metal silicate
deposition, there are number of disadvantages to utilizing water as
the oxygen precursor for metal silicate deposition. For example,
water has limited reactivity and may not be suitable for depositing
a high purity metal silicate film. For example, aluminum silicate
films deposited utilizing water as the oxygen precursor may have a
residual hydrogen content of up to 15 atomic percent, since
employing water as the oxygen precursor may introduce both --H and
--OH species into the metal silicate film. In addition, water can
be easily absorbed on the internal surface of the reaction chamber
and the absorbed water may be difficult to remove from the reaction
chamber, thereby restricting the semiconductor deposition apparatus
that may be utilized when employing water as the oxygen precursor,
especially for showerhead-type reactors, for example.
[0026] As an alternative to water (H.sub.2O), a hydrogen peroxide
(H.sub.2O.sub.2) precursor may be utilized as the oxygen precursor
for metal silicate deposition. There may be a number of benefits of
employing a hydrogen peroxide (H.sub.2O.sub.2) precursor as the
oxygen source for metal silicate deposition. For example, hydrogen
peroxide (H.sub.2O.sub.2) is more reactive than water and comprises
double --OH groups that may produce a more pure metal silicate
film. In addition, a hydrogen peroxide (H.sub.2O.sub.2) precursor
may potentially reduce the chlorine content in metal silicate films
deposited utilizing metal chloride precursors at reduced deposition
temperatures. Furthermore, a hydrogen peroxide (H.sub.2O.sub.2)
precursor may be less aggressive than ozone (O.sub.3) or oxygen
radicals, and has a low diffusivity into the underlying film,
thereby substantially limiting the oxidation of the underlying film
upon which deposition is being performed.
[0027] The embodiments of the disclosure not only utilize hydrogen
peroxide as the oxidizing agent precursor, but also regulate the
temperature of the hydrogen peroxide precursor prior to entry into
the reaction chamber. For example, the temperature of the hydrogen
peroxide precursor may regulated to a temperature of less than
70.degree. C. prior to entry into the reaction chamber, thereby
preventing premature decomposition of the hydrogen peroxide
precursor which could result in the undesirable formation of water
in the reaction chamber and associated problems previously
discussed related to cyclical deposition processes utilizing water
as the oxygen precursor.
[0028] Therefore, the embodiments of the disclosure may include
methods for forming a metal silicate film on a substrate in a
reaction chamber by a cyclical deposition process, the method
comprising: regulating the temperature of a hydrogen peroxide
(H.sub.2O.sub.2) precursor below a temperature of 70.degree. C.
prior to introduction into the reaction chamber; and depositing the
metal silicate film on the substrate by performing at least one
unit deposition cycle of a cyclical deposition process, wherein a
unit deposition cycle comprises: contacting the substrate with a
metal vapor phase precursor; contacting the substrate with a
silicon vapor phase precursor; and contacting the substrate with
the hydrogen peroxide precursor.
[0029] A non-limiting example embodiment of a cyclical deposition
process may include atomic layer deposition (ALD), wherein ALD is
based on typically self-limiting reactions, whereby sequential and
alternating pulses of reactants are used to deposit about one
atomic (or molecular) monolayer of material per deposition cycle.
The deposition conditions and precursors are typically selected to
provide self-saturating reactions, such that an absorbed layer of
one reactant leaves a surface termination that is non-reactive with
the gas phase reactants of the same reactants. The substrate is
subsequently contacted with a different precursor that reacts with
the previous termination to enable continued deposition. Thus, each
cycle of alternated pulses typically leaves no more than about one
monolayer of the desired material. However, as mentioned above, the
skilled artisan will recognize that in one or more ALD cycles more
than one monolayer of material may be deposited, for example, if
some gas phase reactions occur despite the alternating nature of
the process.
[0030] In some embodiments of the disclosure, cyclical deposition
methods may be employed to deposit metal silicate films wherein
each unit deposition cycle comprises at least three deposition
steps or phases and utilizes at least three different precursors or
reactants. Although referred to as "the first," "the second," and
"the third" precursors, these designations do not imply that the
precursors have to be introduced in this order. Thus in some
embodiments, the cyclical deposition methods may start with the
second precursor, or the third precursor. Similarly, although
referred to as first, second, and third phases, they are not
necessarily carried out in this sequence. Additionally, each of the
phases may be repeated prior to a subsequent phase. Additional
phases may also be incorporated into the overall cyclical
deposition cycle.
[0031] A cyclical deposition process for depositing a metal
silicate film may comprise an ALD-type process and a unit
deposition cycle may comprise, exposing the substrate to a first
precursor, removing any unreacted first precursor and reaction
byproducts from the reaction chamber, exposing the substrate to a
second precursor, followed by a second removal step, and exposing
the substrate to a third precursor, followed by a third removal
step. In some embodiments, the first precursor may comprise a metal
vapor phase precursor (`the metal precursor"), the second precursor
may comprise a silicon vapor phase precursor ("the silicon
precursor"), and the third precursor may comprise a hydrogen
peroxide precursor ("the oxygen precursor").
[0032] Precursors may be separated by inert gases, such as argon
(Ar) or nitrogen (N.sub.2), to prevent gas-phase reactions between
precursors and enable self-saturating surface reactions. In some
embodiments, however, the substrate may be moved to separately
contact a first precursor, a second precursor, and a third
precursor. Because the reactions self-saturate, strict temperature
control of the substrates and precise dosage control of the
precursors may not be required. However, the substrate temperature
is preferably such that an incident gas species does not condense
into monolayers nor decompose on the surface. Surplus chemicals and
reaction byproducts, if any, are removed from the substrate
surface, such as by purging the reaction space or by moving the
substrate, before the substrate is contacted with the next reactive
chemical. Undesired gaseous molecules can be effectively expelled
from a reaction space with the help of an inert purging gas. A
vacuum pump may be used to assist in the purging.
[0033] Reactors capable of being used to deposit metal silicate
films can be used for the deposition processes described herein.
Such reactors include ALD reactors, as well as CVD reactors,
configured to provide the precursors. According to some
embodiments, a showerhead reactor may be used. According to some
embodiments, cross-flow, batch, mini-batch, or spatial ALD reactors
may be used.
[0034] In some embodiments of the disclosure, a batch reactor may
be used. In some embodiments, a vertical batch reactor may be
utilized. In other embodiments, the batch reactor comprises a
mini-batch reactor configured to accommodate 10 or fewer wafers, 8
or fewer wafers, 6 or fewer wafers, 4 or fewer wafers, or 2 or
fewer wafers. In some embodiments in which a batch reactor is used,
wafer-to-wafer non-uniformity is less than 3% (1 sigma), less than
2%, less than 1%, or even less than 0.5%.
[0035] The deposition processes described herein may optionally be
carried out in a reactor or reaction chamber connected to a cluster
tool. In a cluster tool, because each reaction chamber is dedicated
to one type of process, the temperature of the reaction chamber in
each module can be kept constant, which improves the throughput
compared to a reactor in which the substrate is heated up to the
process temperature before each run. Additionally, in a cluster
tool it is possible to reduce the time to pump the reaction chamber
to the desired process pressure levels between substrates. In some
embodiments of the disclosure, the deposition process may be
performed in a cluster tool comprising multiple reaction chambers,
wherein each individual reaction chamber may be utilized to expose
the substrate to an individual precursor gas and the substrate may
be transferred between different reaction chambers for exposure to
multiple precursors gases, the transfer of the substrate being
performed under a controlled ambient to prevent
oxidation/contamination of the substrate.
[0036] As a non-limiting example, a first reaction chamber may be
utilized to passivate the surface of the substrate by contacting
the substrate with a gas-phase sulfur precursor. The passivated
substrate may then be transferred to a second reaction chamber
under controlled conditions, such as, temperature, pressure, and
gaseous environment, and subsequently subjected to a plurality of
deposition cycles for depositing a metal silicate film over the
passivated substrate surface, the cyclical deposition process being
carried out in the second reaction chamber.
[0037] A stand-alone reactor may be equipped with a load-lock. In
that case, it is not necessary to cool down the reaction chamber
between each run. In some embodiments, a deposition process for
depositing a metal silicate film may comprise a plurality of
deposition cycles, i.e., a plurality of unit cycles, for example, a
plurality of ALD cycles or a plurality of cyclical CVD cycles.
[0038] In some embodiments, one or more cyclical deposition
processes may be used to deposit the metal silicate films of the
current disclosure on a substrate and the cyclical deposition
processes may comprise one or more ALD-type processes. In some
embodiments, a cyclical deposition process may comprise one or more
hybrid ALD/CVD processes or one or more cyclical CVD process. For
example, in some embodiments, the growth rate of an ALD process may
be low compared with a CVD process. One approach to increase the
growth rate may be that of operating at a higher substrate
temperature than that typically employed in an ALD process,
resulting in at least a portion of the deposition being provided by
a chemical vapor deposition type process, but still taking
advantage of the sequential introduction of precursors, such a
process may be referred to as cyclical CVD. In some embodiments, a
cyclical CVD process may comprise the introduction of two or more
precursors into the reaction chamber wherein there may be a time
period of overlap between the two or more precursors in the
reaction chamber resulting in both an ALD component of the
deposition and a CVD component of the deposition. For example, a
cyclical CVD process may comprise the continuous flow of a first
precursor and the periodic pulsing of a second precursor and/or a
third precursor into the reaction chamber.
[0039] As a non-limiting example the metal silicate films of the
current disclosure may be deposited by a cyclical deposition
process such as exemplary ALD process 100 and its constituent
process blocks, as illustrated with reference to FIG. 1. The
exemplary ALD process 100 may commence by means of a process block
110 comprising, providing a substrate into a reaction chamber and
heating the substrate to a deposition temperature.
[0040] In some embodiments of the disclosure, the substrate may
comprise a planar substrate or a patterned substrate including high
aspect ratio features, such as, for example, trench structures
and/or fin structures. The substrate may comprise one or more
materials including, but not limited to, silicon (Si), germanium
(Ge), germanium tin (GeSn), silicon germanium (SiGe), silicon
germanium tin (SiGeSn), silicon carbide (SiC), or a group III-V
semiconductor material, such as, for example, gallium arsenide
(GaAs), gallium phosphide (GaP), or gallium nitride (GaN). In some
embodiments of the disclosure, the substrate may comprise an
engineered substrate wherein a surface semiconductor layer is
disposed over a bulk support with an intervening buried oxide (BOX)
disposed there between.
[0041] Patterned substrates may comprise substrates that may
include semiconductor device structures formed into or onto a
surface of the substrate, for example, a patterned substrate may
comprise partially fabricated semiconductor device structures, such
as, for example, transistors and/or memory elements. In some
embodiments, the substrate may contain monocrystalline surfaces
and/or one or more secondary surfaces that may comprise a
non-monocrystalline surface, such as a polycrystalline surface
and/or an amorphous surface. Monocrystalline surfaces may comprise,
for example, one or more of silicon (Si), silicon germanium (SiGe),
silicon carbide (SiC), germanium tin (GeSn), germanium (Ge), or a
group III-V semiconductor. Polycrystalline or amorphous surfaces
may include dielectric materials, such as oxides, oxynitrides or
nitrides, such as, for example, silicon oxides and silicon
nitrides.
[0042] The substrate may be disposed within a suitable reaction
chamber, such as ALD reaction chambers and CVD reaction chambers as
previously described, and the exemplary ALD process 100 may
continue by heating the substrate to a desired deposition
temperature prior to film deposition. For example, the substrate
may be heated to a substrate temperature of less than approximately
500.degree. C., or less than approximately 400.degree. C., or less
than approximately 300.degree. C., or less than approximately
200.degree. C., or even less than approximately 100.degree. C. In
some embodiments of the disclosure, the substrate temperature
during the deposition process may be between 100.degree. C. and
500.degree. C., or between 200.degree. C. and 300.degree. C.
[0043] In addition to achieving a desired deposition temperature,
i.e., a desired substrate temperature, the exemplary ALD process
100 may also regulate the pressure within the reaction chamber to
obtain desirable characteristics of the metal silicate film. For
example, in some embodiments of the disclosure, the exemplary ALD
process 100 may be performed within a reaction chamber regulated to
a reaction chamber pressure of less than 100 Torr, or less than 10
Torr, or even less than 1 Torr. For example, the exemplary ALD
process 100 may be performed within a reaction chamber regulated to
a reaction chamber pressure between approximately 1 Torr and
approximately 4 Torr.
[0044] Upon heating the substrate to a desired deposition
temperature and regulating the reaction chamber pressure to a
desired set-point, the exemplary ALD process 100 may continue with
a cyclical deposition phase 105 by means of a process block 120
comprising, contacting the substrate with a first vapor phase
reactant and particularly, in some embodiments, contacting the
substrate with a metal vapor phase precursor, i.e., the metal
precursor ("the metal stage").
[0045] In some embodiments of the disclosure, the metal vapor phase
precursor may comprise at least one of a hafnium precursor, an
yttrium precursor, a zirconium precursor, an aluminum precursor, a
scandium precursor, a cerium precursor, an erbium precursor, or a
strontium precursor.
[0046] In some embodiments, the metal vapor phase precursor may
comprise a metal halide, such as, for example, a metal chloride, a
metal iodide, or a metal bromide.
[0047] In some embodiments, the metal vapor phase precursor may
comprise a metalorganic precursor, including, but not limited to,
alky amide based metal precursors, cyclopentadienyl based metal
precursors, amidinate based metal precursors, diketonate based
metal precursors, or amide based metal precursors.
[0048] In some embodiments, a hafnium precursor may comprise at
least one of hafnium tetrachloride (HfCl.sub.4), or
tetrakis-ethylmethylaminohafnium (TEMAHf). In some embodiments, an
yttrium precursor may comprise at least one of Y(EtCp).sub.3,
tris(methylcyclopentadienyl)yttrium (Y(MeCp).sub.3),
tris(N,N'-diisopropylacetamidinato)yttrium (TDIPAY),
(Y(THD).sub.3), tris(2,2,6,6-tetramethyl-3,5-octanedionato)yttrium
(Y(tmod).sub.3), or tris[N,N-bis(trimethylsilyl)amide]yttrium. In
some embodiments, a zirconium precursor may comprise at least one
of zirconium tetrachloride (ZrCl.sub.4), or
tetrakis-ethylmethylaminozirconium (TEMAZr). In some embodiments, a
scandium precursor may comprise at least one of
tris(cyclopentadienyl)scandium, or
tris(methylcyclopentadienyl)scandium. In some embodiments, an
erbium precursor may comprise at least one of
tris(cyclopentadienyl)erbium, or
tris(methylcyclopentadienyl)erbium. In some embodiments, a cerium
precursor may comprise tris(cyclopentadienyl)cerium. In some
embodiments, a strontium precursor may comprise
bis(triisopropylcyclopentadienyl)strontium.
[0049] In some embodiments of the disclosure, the metal vapor phase
precursor may comprise an aluminum precursor selected from the
group comprising: trimethylaluminum (TMA), triethylaluminum (TEA),
dimethylaluminumhydride (DMAH), tritertbutylaluminum (TTBA),
aluminum trichloride (AlCl.sub.3), or dimethylaluminumisopropoxide
(DMAI).
[0050] In some embodiments of the disclosure, contacting the
substrate with the metal vapor phase precursor may comprise
contacting the substrate for a time period of between about 0.01
seconds and about 60 seconds, between about 0.05 seconds and about
10 seconds, or between about 0.1 seconds and about 5.0 seconds. In
addition, during the contacting of the substrate with the metal
vapor phase precursor, the flow rate of the first vapor phase
reactant may be less than 2000 sccm, or less than 500 sccm, or even
less than 100 sccm. In addition, during the contacting of the
substrate with the metal vapor phase precursor the flow rate of the
metal vapor phase reactant may range from about 1 to 2000 sccm,
from about 5 to 1000 sccm, or from about 10 to about 500 sccm.
[0051] The exemplary ALD process 100 of FIG. 1 may continue by
purging the reaction chamber. For example, excess metal vapor phase
precursor and reaction byproducts (if any) may be removed from the
surface of the substrate, e.g., by pumping with an inert gas. In
some embodiments of the disclosure, the purge process may comprise
a purge cycle wherein the substrate surface is purged for a time
period of less than approximately 5.0 seconds, or less than
approximately 3.0 seconds, or even less than approximately 2.0
seconds. Excess metal vapor phase precursor and any possible
reaction byproducts may be removed with the aid of a vacuum,
generated by a pumping system in fluid communication with the
reaction chamber.
[0052] Upon purging the reaction chamber with a purge cycle the
exemplary ALD process 100 may continue with a second stage of the
cyclical deposition phase 105 by means of a process block 130 which
comprises, contacting the substrate with a second vapor phase
precursor, and particularly contacting the substrate with a silicon
vapor phase precursor ("the silicon stage").
[0053] In some embodiments of the disclosure, the silicon vapor
phase precursor may be selected from the group comprising:
silanediamine N,N,N',N-tetraethyl (C.sub.8H.sub.22N.sub.2Si), BTBAS
(bis(tertiarybutylamino)silane), BDEAS (bis(diethylamino)silane),
TDMAS (tris(dimethylamino)silane), hexakis(ethylamino)disilane
(Si.sub.2(NHC.sub.2H.sub.5).sub.6), hexachlorodisilane (HCDS), or
pentachlorodisilane(PCDS).
[0054] In some embodiments, the silicon vapor phase precursor may
comprise a silane, such as, for example, silane (SiH.sub.4),
disilane (Si.sub.2H.sub.6), trisilane (Si.sub.3H.sub.8),
tetrasilane (Si.sub.4H.sub.10) or higher order silanes with the
general empirical formula Si.sub.xH.sub.(2x+2).
[0055] In some embodiments, the silicon vapor phase precursor may
comprise a silicon halide compound, such as, for example, a silicon
halide having the general formula given as: Si.sub.xW.sub.yH.sub.z,
wherein "W" is a halide selected from the group consisting of
Fluorine (F), Chlorine (Cl), Bromine (Br), and Iodine (I), "x" and
"y" are integers greater than zero, and "z" is an integer greater
than or equal to zero. In some embodiments, the silicon halide
precursor may be selected from the group consisting of silicon
fluorides (e.g., SiF.sub.4), silicon chlorides (e.g., SiCl.sub.4),
silicon bromides (e.g., SiBr.sub.4), and silicon iodides (e.g.,
SiI.sub.4). In some embodiments, the silicon vapor phase precursor
may comprise silicon tetrachloride (SiCl.sub.4).
[0056] In some embodiments, the silicon vapor phase precursor may
comprise an aminosilane, such as, bis-ethylaminosilane, for
example.
[0057] In some embodiments of the disclosure, contacting the
substrate with the silicon vapor phase precursor may comprise
contacting the silicon precursor to the substrate for a time period
of between about 0.01 seconds and about 60 seconds, between about
0.05 seconds and about 10 seconds, or between about 0.1 seconds and
about 5.0 seconds. In addition, during the contacting of the
substrate with the silicon precursor, the flow rate of the silicon
precursor may be less than 2000 sccm, or less than 500 sccm, or
even less than 100 sccm. In addition, during the contacting of the
substrate with the silicon precursor the flow rate of the silicon
precursor may range from about 1 to 2000 sccm, from about 5 to 1000
sccm, or from about 10 to about 500 sccm.
[0058] Upon contacting the substrate with the silicon vapor phase
precursor, the exemplary ALD process 100 may proceed by purging the
reaction chamber. For example, excess silicon precursor and
reaction byproducts (if any) may be removed from the surface of the
substrate, e.g., by pumping whilst flowing an inert gas. In some
embodiments of the disclosure, the purge process may comprise
purging the substrate surface for a time period of between
approximately 0.1 seconds and approximately 10 seconds, or between
approximately 0.5 seconds and approximately 3 seconds, or even
between approximately 1 second and 2 seconds.
[0059] Upon purging the reaction chamber with a purge cycle, the
exemplary ALD process 100 may continue with a third stage of the
cyclical deposition phase 105 by means of a--process block 140
which comprises, contacting the substrate with a third vapor phase
reactant, and particularly contacting the substrate with hydrogen
peroxide (H.sub.2O.sub.2) ("the oxygen stage").
[0060] In some embodiments, the temperature of the hydrogen
peroxide precursor may be carefully regulated prior to entering the
reaction chamber thereby preventing premature decomposition of the
hydrogen peroxide precursor. In some embodiments of the disclosure,
the reaction chamber may comprise a showerhead reactor utilizing a
showerhead gas distribution mechanism to introduce the precursors,
and particularly the hydrogen peroxide precursor, into the reaction
chamber. In some embodiments, the methods of the current disclosure
may comprise regulating the temperature of the showerhead
distribution mechanism to a temperature below 70.degree. C., or
below 60.degree. C., or even below 50.degree. C. In some
embodiments, the temperature of the showerhead distribution
mechanism may be regulated to a temperature between approximately
50.degree. C. and approximately 120.degree. C.
[0061] In some embodiments, in addition to the temperature
regulation of the showerhead gas distribution mechanism the
temperature of the chamber walls of the reaction chamber walls may
also be regulated to prevent premature decomposition of the
hydrogen peroxide precursor. For example, in some embodiments, the
reaction chamber may comprise a "cold-wall" reaction chamber,
wherein the temperature of the chamber walls is maintained below
that of the deposition temperature of the substrate. Therefore, in
some embodiments, the methods of the current disclosure may further
comprise regulating the temperature of at least one chamber wall of
the reaction chamber at least at those portions of the least one
chamber wall exposed to the precursors, and particularly to the
hydrogen peroxide precursor, to a temperature below 70.degree. C.,
or below 60.degree. C., or even below 50.degree. C. In some
embodiments, the temperature of at least one chamber wall of the
reaction chamber may be regulated at a temperature between
approximately 50.degree. C. and approximately 120.degree. C.
[0062] For more detailed information on temperature regulation of a
showerhead gas distribution mechanism and temperature regulation of
the chamber walls of a reaction chamber, see U.S. application Ser.
No. 15/636,307, filed on Jun. 28, 2017, titled "METHODS FOR
DEPOSITING A TRANSITION METAL NITRIDE FILM ON A SUBSTRATE BY
ATOMICLAYER DEPOSITION AND RELATED DEPOSITION APPARATUS," all of
which is hereby incorporated by reference.
[0063] The careful regulation of the temperature of the showerhead
gas distribution mechanism and the chamber walls of the reaction
chamber may substantially prevent the premature decomposition of
the hydrogen peroxide precursor prior to interaction with the
heated substrate. Therefore, in some embodiments, the hydrogen
peroxide precursor may decompose proximate to the substrate.
[0064] In some embodiments of the disclosure, contacting the
substrate with the hydrogen peroxide precursor may comprise,
contacting the substrate with the hydrogen peroxide precursor for a
time period of between about 0.01 seconds and about 60 seconds,
between about 0.05 seconds and about 10 seconds, or between about
0.1 seconds and about 5.0 seconds. In addition, during the
contacting of substrate with the hydrogen peroxide precursor, the
flow rate of the hydrogen peroxide precursor may be less than 2000
sccm, or less than 500 sccm, or even less than 100 sccm. In
addition, during the contacting the substrate with the hydrogen
peroxide precursor the flow rate of the hydrogen peroxide precursor
may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or
from about 10 to about 500 sccm.
[0065] Upon contacting the substrate with the hydrogen peroxide
precursor, the exemplary ALD process 100 may proceed by purging the
reaction chamber. For example, excess hydrogen peroxide precursor
and reaction byproducts (if any) may be removed from the surface of
the substrate, e.g., by pumping whilst flowing an inert gas. In
some embodiments of the disclosure, the purge process may comprise
purging the substrate surface for a time period of between
approximately 0.1 seconds and approximately 10 seconds, or between
approximately 0.5 seconds and approximately 3 seconds, or even
between approximately 1 second and 2 seconds.
[0066] Upon completion of the purge of the third vapor phase
reactant, i.e., the hydrogen peroxide precursor (and any reaction
byproducts) from the reaction chamber, the cyclic deposition phase
105 may continue by means of a decision gate 150, wherein the
decision gate 150 is dependent on the thickness of the metal
silicate film deposited. For example, if the metal silicate film is
deposited at an insufficient thickness for a desired application,
then the cyclical deposition phase 105 may be repeated by returning
to the process block 120 and continuing through a further
deposition cycle, wherein a unit deposition cycle may comprise,
contacting the substrate with a metal precursor (process block
120), purging the reaction chamber, contacting the substrate with a
silicon precursor (process block 130), purging the reaction
chamber, contacting the substrate with a hydrogen peroxide
precursor (process block 140), and again purging the reaction
chamber. A unit deposition cycle of cyclical deposition phase 105
may be repeated one or more times until a desired thickness of a
metal silicate film is deposited over the substrate. Once the metal
silicate film has been deposited to the desired thickness the
exemplary ALD process 100 may exit via a process block 160 and the
substrate, with the metal silicate film thereon, may be subjected
to further processing for the formation of a semiconductor device
structure.
[0067] It should be appreciated that in some embodiments of the
disclosure, the order of contacting of the substrate with the metal
precursor, the silicon precursor, and the hydrogen peroxide
precursor may be such that the sequence of contacting the substrate
with the different precursors may be carried out in any order
within a unit deposition cycle. As a non-limiting example, the
substrate may be first contacted with the hydrogen peroxide
precursor, followed by the metal precursor, and subsequently by the
silicon precursor. In addition, in some embodiments, the cyclical
deposition phase 105 of exemplary ALD process 110 may comprise,
contacting the substrate with each individual precursor one or more
time prior to progressing to the next stage of the deposition
cycle. For example, a unit deposition cycle may incorporate
multiple pulses of the metal precursor, and/or the silicon
precursor, and/or the hydrogen peroxide precursor.
[0068] In some embodiments of the disclosure, the growth rate of
the metal silicate film may be from about 0.005 .ANG./cycle to
about 5 .ANG./cycle, or from about 0.01 .ANG./cycle to about 2.0
.ANG./cycle, or from about 0.1 .ANG./cycle to about 1.5
.ANG./cycle. In some embodiments of the disclosure, the growth rate
of the metal silicate film is approximately 1.0 .ANG./cycle.
[0069] In some embodiments of the disclosure, the metal silicate
films may be deposited on the surface of the substrate
substantially without, or without, an incubation period. In more
detail, prior cyclical deposition processes utilized for the
deposition of metal silicate films generally require a plurality of
deposition cycles prior to any discernable deposition on the
surface of the substrate. In contrast, the embodiments of the
current disclosure which utilize a hydrogen peroxide precursor as
the oxidizing agent with stringent temperature control over the
hydrogen peroxide precursor prior to interaction with the heated
substrate, results in immediate deposition of the metal silicate
film upon the substrate surface from the initial deposition cycle
thereby eliminating any incubation period. For example, deposition
of a metal silicate film may be achieved on the substrate utilizing
less than 10 deposition cycles, or less than 5 deposition cycles,
or less than 2 deposition cycles, or even 1 deposition cycle.
[0070] The metal silicate films deposited by the cyclical
deposition processes disclosed herein may be continuous films. In
some embodiments, the metal silicate film may be continuous at a
thickness below approximately 100 nanometers, or below
approximately 60 nanometers, or below approximately 50 nanometers,
or below approximately 40 nanometers, or below approximately 30
nanometers, or below approximately 20 nanometers, or below
approximately 10 nanometers, or below approximately 5 nanometers,
or below approximately 2 nanometers, or below approximately 1
nanometer, of even below approximately 0.5 nanometers. The
continuity referred to herein can be physical continuity or
electrical continuity. In some embodiments of the disclosure the
thickness at which the metal silicate film may be physically
continuous may not be the same as the thickness at which the metal
silicate film is electrically continuous, and vice versa.
[0071] In some embodiments of the disclosure, the metal silicate
films deposited according to the cyclical deposition processes
described herein may have a thickness from about 20 nanometers to
about 100 nanometers, or about 20 nanometers to about 60
nanometers. In some embodiments, a metal silicate film deposited
according to some of the embodiments described herein may have a
thickness greater than about 20 nanometers, or greater than about
30 nanometers, or greater than about 40 nanometers, or greater than
about 50 nanometers, or greater than about 60 nanometers, or
greater than about 100 nanometers, or greater than about 250
nanometers, or greater than about 500 nanometers, or greater. In
some embodiments a metal silicate film deposited according to some
of the embodiments described herein may have a thickness of less
than about 50 nanometers, or less than about 30 nanometers, or less
than about 20 nanometers, or less than about 15 nanometers, or less
than about 10 nanometers, or less than about 5 nanometers, or less
than about 3 nanometers, or less than about 2 nanometers, or even
less than about 1 nanometer.
[0072] The cyclical deposition processes, such as the exemplary ALD
processes described herein, may be utilized to deposit metal
silicate films with a greater purity than those formed by prior
deposition methods. As a non-limiting example, the metal silicate
films of the current disclosure may comprise less than about 1
atomic-% carbon, or less than 0.5 atomic-% carbon, or less than 0.2
atomic-% carbon. As a further non-limiting example, the metal
silicate films of the current disclosure may comprise less than
about 5 atomic-% hydrogen, or less than 4 atomic-% hydrogen, or
even less than 3 atomic-% hydrogen. In the embodiments outlined
herein, the atomic concentration of an element may be determined
utilizing Rutherford backscattering (RBS).
[0073] In some embodiments of the disclosure, the metal silicate
films of the current disclosure may be deposited utilizing a halide
precursor, e.g., silicon tetrachloride (SiCl.sub.4) as the silicon
precursor, and the deposition methods of the current disclosure may
enable the deposition of metal silicate films with a reduced
residual halide content. For example, the metal silicate films of
the current disclosure may comprise less than about 0.2 atomic-%
halide, or less than about 0.1 atomic-% halide, or less than 0.05
atomic-% halide, wherein the halide may comprise at least one of
fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). As a
non-limiting example, the metal silicate film of the current
disclosure may be deposited utilizing a silicon chloride precursor
(e.g., SiCl.sub.4) and the metal silicate films may comprise less
than 0.2 atomic-% chlorine, or less than about 0.1 atomic-%
chlorine, or even less than about 0.05% atomic-% chlorine.
[0074] The embodiments of the disclosure may be employed for
forming high quality metal silicate films and particular metal
silicate films from the group comprising: hafnium silicate films
(Hf.sub.xSi.sub.yO.sub.z), ytrrium silicate films
(Y.sub.xSi.sub.yO.sub.z), zirconium silicate films
(ZrxSi.sub.yO.sub.z), aluminum silicate films
(Al.sub.xSi.sub.yO.sub.z), scandium silicate films
(Sc.sub.xSi.sub.yO.sub.z), cerium silicate films
(Ce.sub.xSi.sub.yO.sub.z), erbium silicate films
(Er.sub.xSi.sub.yO.sub.z), or strontium silicate films
(Sr.sub.xSi.sub.yO.sub.z).
[0075] In some embodiments of the disclosure, the metal silicate
films of the current disclosure may comprises a silicon content of
greater than approximately 10 atomic-%, or greater than
approximately 20 atomic-%, or greater than approximately 30
atomic-%, or greater than approximately 40 atomic-%, or greater
than approximately 50 atomic-%, or even greater than approximately
60 atomic-%. In some embodiments, the metal silicate films of the
current disclosure may have a silicon content between approximately
10 atomic-% and approximately 60 atomic %, or between approximately
10 atomic-% and approximately 30 atomic-%. In some embodiments, the
metal silicate films of the current disclosure may have a silicon
content of less than 10 atomic-%.
[0076] As a non-limiting example, the metal silicate film of the
current disclosure may comprise an aluminum silicate film
(Al.sub.xSi.sub.yO.sub.z) with an atomic percentage of silicon
between approximately 10 atomic-% and approximately 60 atomic-%. As
a further non-limiting example, the metal silicate film of the
current disclosure may comprise an aluminum silicate film
(Al.sub.xSi.sub.yO.sub.z) with an atomic percentage of silicon
between approximately 10 atomic-% and approximately 30 atomic-%, or
an atomic percentage of silicon less than 10 atomic-%.
[0077] In some embodiments of the disclosure, the metal silicate
films may be deposited on a three-dimensional structure, e.g., a
non-planar substrate comprising high aspect ratio features. In some
embodiments, the step coverage of the metal silicate film may be
equal to or greater than about 50%, or greater than about 60%, or
greater than 70%, or greater than 80%, or greater than about 90%,
or greater than about 95%, or greater than about 98%, or greater
than about 99%, or greater in structures having aspect ratios
(height/width) of more than about 2, or more than about 5, or more
than about 10, or more than about 25, or more than about 50, or
even more than about 100.
[0078] As previously stated, the substrate upon which the metal
silicate film is deposited may comprise a patterned substrate that
may include semiconductor device structures formed into or onto a
surface of the substrate, for example, a patterned substrate may
comprise partially fabricated semiconductor device structures, such
as, for example, transistors and/or memory elements.
[0079] In some embodiments of the disclosure, the substrate may
comprise a plurality of channel regions and the metal silicate film
may be deposited directly on the plurality of channel regions,
wherein the term "channel region" may refer to a region of a
semiconductor device structure in which carrier flow may be
controlled, e.g., by biasing of a gate electrode.
[0080] As a non-limiting example, FIG. 2 illustrates semiconductor
device structure 200, which may comprise a planar NMOS FET device.
Semiconductor device structure 200 may include a substrate 202,
which may include p-type dopants. Disposed in the or on the
substrate are source/drain regions 214, the source/drain regions
214 comprising a phosphorus doped silicon film 218. A channel
region 212 may be disposed between the source/drain regions 214.
Although a single channel region 212 is illustrated in FIG. 2 it
should be appreciated that the substrate upon which deposition of
the metal silicate is performed may comprise a plurality of channel
regions. In some embodiments, the plurality of channels regions may
comprise silicon germanium (Si.sub.1-xGe.sub.x) wherein x may be
between approximately 0 and approximately 0.25, or between
approximately 0 and approximately 0.50, or between approximately
0.01 and approximately 0.50, or even between 0.05 and approximately
0.25.
[0081] In some embodiments of the disclosure, an interface layer
209 comprising a metal silicate may be disposed directly on the
channel region 212 and the metal silicate interface layer 209 may
be deposited directly on the channel region utilizing the cyclical
deposition processes described herein. For example, the metal
silicate interface layer 209 may comprise an aluminum silicate
(Al.sub.xSi.sub.yO.sub.z) with an atomic percentage of silicon
between approximately 10 atomic-% and approximately 60 atomic-%, or
between approximately 10 atomic-% and approximately 30 atomic-%, or
less than approximately 10 atomic-%.
[0082] In some embodiments of the disclosure, prior to the
deposition of the metal silicate film directly on the plurality of
channels regions, the exposed surface of the plurality of the
channels regions may be passivated. In more detail, the interface
between the interface layer 209 and the channel region 212 commonly
includes a large interface trap density (D.sub.it). The high
D.sub.it values are thought to result from vacancies and dangling
bonds at the surface of the channel region comprising a silicon
germanium material and may deleteriously affect the performance of
semiconductor devices formed utilizing the plurality of silicon
germanium channel regions.
[0083] Therefore, the embodiments of the disclosure further
comprise, passivating a surface of the plurality of channel regions
prior to deposition of the metal silicate film, wherein passivating
the surface of the plurality of channels regions comprises,
exposing the exposed surface of the plurality of channel regions to
a gas-phase sulfur precursor. In some embodiments, the gas-phase
sulfur precursor may comprise at least one of (NH.sub.4).sub.2S,
H.sub.2S, NH.sub.4HS, or an organosulfur compound. More information
related to the passivation of semiconductor channel region
utilizing a gas-phase sulfur precursor may found in U.S.
Publication No. 2014/0027884, filed on Jul. 12, 2013, titled
"SYSTEM AND METHOD FOR GAS-PHASE SULFUR PASSIVATION OF A
SEMICONDUCTOR SURFACE," all of which is hereby incorporated by
reference.
[0084] In some embodiments, the interface trap density at an
interface between the plurality of channel regions, such as channel
region 212, and the metal silicate film, i.e., the interface layer
209, is less than 7 e.sup.12 cm.sup.-2 eV.sup.-1, or less than 1
e.sup.12 cm.sup.-2 eV.sup.-1, or even less than 7 e.sup.11
cm.sup.-2 eV.sup.-1 for mid-gap states. In addition, in some
embodiments, the metal silicate film, i.e., the interface layer
209, may have an effective oxide charge density of less than 5
e.sup.10 cm.sup.-2, or less than 3 e.sup.10 cm.sup.-2, or even less
than 2 e.sup.10 cm.sup.-2.
[0085] In some embodiments, the methods of the disclosure may
further comprise depositing a high-k dielectric material on the
metal silicate film, such that the metal silicate film forms an
interface layer disposed directly between the plurality of channel
regions and the high-k dielectric material. For example, the
semiconductor device structure 200 may comprise a high-k dielectric
material 207 disposed directly on the metal silicate interface
layer 209. In some embodiments, the high-k dielectric material 207
may comprise a metallic oxide having a dielectric constant greater
than approximately 7. In some embodiments, the high-k metallic
oxide may comprise at least one of hafnium oxide (HfO.sub.2),
tantalum oxide (Ta.sub.2O.sub.5), zirconium oxide (ZrO.sub.2),
titanium oxide (TiO.sub.2), hafnium silicate (HfSiO.sub.x),
aluminum oxide (Al.sub.2O.sub.3) or lanthanum oxide
(La.sub.2O.sub.3), or mixtures/laminates thereof.
[0086] A gate electrode may be deposited directly on the high-k
dielectric material, such as gate electrode 208 disposed directly
on the high-k dielectric material 207. In some embodiments, the
gate electrode may comprise one or more of a metal, a metal
nitride, or a metal carbide film, such as, for example, a titanium
aluminum carbide (TiAlC). In addition, gate spacers 210 may be
disposed over the substrate 202.
[0087] The embodiments of the disclosure may also provide
semiconductor device structures, such as, for example, the
semiconductor device structure 200 of FIG. 2. The semiconductor
device structure may comprise, a silicon germanium
(Si.sub.1-xGe.sub.x) channel region 212, an interface layer 209
comprising an aluminum silicate film disposed directly on the
silicon germanium (Si.sub.1-xGe.sub.x) channel region 212; and a
high-k dielectric material 207 disposed directly on the interface
layer, wherein an interface trap density at an interface between
the silicon germanium (Si.sub.1-xGe.sub.x) channel region 212 and
the interface layer 209 is less than about 7 e.sup.11 cm.sup.-2
eV.sup.-1 for mid-gap states.
[0088] In some embodiments of the disclosure, the silicon germanium
(Si.sub.1-xGe.sub.x) channel region 212 has germanium content
wherein x is between approximately 0 and approximately 0.50, or
between approximately 0 and approximately 0.25, or between
approximately 0.01 and approximately 0.50, or between approximately
0.05 and approximately 0.25. In addition, the aluminum silicate
film 209 may have an atomic percentage of silicon between
approximately 10 atomic-% and approximately 60 atomic-%, or between
approximately 10 atomic-% and approximately 30 atomic-%, or even
less than 10 atomic-%. In some embodiments, the aluminum silicate
film 209 may have an effective oxide charge density of less than 5
e.sup.10 cm.sup.-2. In addition, the interface layer comprising the
aluminum silicate film 209 may have a thickness of less than 1
nanometer, or less than 0.5 nanometers, or even less than 0.25
nanometers.
[0089] In some embodiments, the high-k dielectric material 207 may
comprise a metallic oxide having a dielectric constant greater than
approximately 7. In addition, a gate electrode 208 may be disposed
over the high-k dielectric material 207 and gate spacers 210 may be
disposed over the substrate 202.
[0090] The embodiments of the disclosure may also provide
semiconductor processing apparatus configured for performing the
cyclical deposition methods described herein. In more detail, FIG.
3 illustrates an exemplary semiconductor processing apparatus 300
which comprises a reaction chamber 302 and a precursor delivery
system 312. The precursor delivery system 312 may be configured for
supplying precursor(s) and purge gas to the reaction chamber 302.
It should be noted that the semiconductor processing apparatus 300
is a simplified schematic version of an exemplary semiconductor
processing apparatus and does not contain each and every element,
i.e., such as each and every valve, gas line, heating element, and
reactor component, etc. The semiconductor processing apparatus 300
of FIG. 3 provides the key features of the apparatus to provide
sufficient disclosure to one of ordinary skill in the art.
[0091] The exemplary semiconductor processing apparatus 300 may
comprise a reaction chamber 302 constructed and arranged to hold at
least a substrate 304. In some embodiments, the reaction chamber
302 may be configured for one or more of a deposition process, an
etching process, or a cleaning process. For example, the reaction
chamber 302 may be configured for cyclical deposition processes,
such as, for example, atomic layer deposition (ALD) processes, or
cyclical chemical vapor deposition (CCVD) processes. In some
embodiments, the reaction chamber may include one or more
temperature controlled chamber walls wherein the chamber walls may
be regulated at a temperature below approximately 70.degree. C.,
such a regulation of the chamber walls may prevent premature
decomposition of the hydrogen peroxide precursor utilized in the
cyclical deposition processes of the current disclosure and further
details regarding the temperature control of reaction chamber walls
may be found in U.S. application Ser. No. 15/636,307, filed on Jun.
28, 2017, titled "METHODS FOR DEPOSITING A TRANSITION METAL NITRIDE
FILM ON A SUBSTRATE BY ATOMIC LAYER DEPOSITION AND RELATED
DEPOSITION APPARATUS," all of which is hereby incorporated by
reference.
[0092] In some embodiments, the substrate 304 may be disposed in
the reaction chamber 302 and held in position by a susceptor 308
configured to retain at least one substrate thereon. The susceptor
may comprise a heater 310 configured to heat the substrate 304 to a
suitable process temperature.
[0093] The precursor delivery system 312 may comprise one or more
precursor sources 314A, 314B, and 314C constructed and arranged to
provide a vapor phase precursor to the reaction chamber 302. For
example, the precursor sources 314A, 314B, and 314C may comprise a
solid precursor, a liquid precursor, a vapor precursor, or mixtures
thereof. In some embodiments, the precursor source 314A may
comprise a metal vapor phase precursor, such as, an aluminum
precursor (e.g., trimethylaluminum (TMA)). In some embodiments, the
precursor source 314B may comprise a silicon vapor phase precursor,
such as, a silicon halide (e.g., silicon tetrachloride
(SiCl.sub.4)). In some embodiments, the precursor source 314C may
comprise a hydrogen peroxide (H.sub.2O.sub.2) precursor.
[0094] The precursor delivery system 312 may also comprise a source
vessel 316 configured for storing and dispensing a purge gas to the
reaction chamber 302, such as, for example, nitrogen, helium, or
argon. The precursor delivery system 312 may also comprise a source
vessel 318 configured for storing and dispensing a gas-phase sulfur
precursor to the reaction chamber 302 to enable passivation of
surfaces of the substrate 304 disposed within the reaction chamber
302, such as, hydrogen sulfide (H.sub.2S), for example.
[0095] The precursor delivery system 312 may also comprise valves
322A, 322B, 322C, 322D, and 322E, e.g., shut-off valves, which may
be associated with the precursor sources 314A, 314B, and 314C, as
well the source vessel 316 containing purge gas, and the source
vessel 318 containing a gas-phase sulfur precursor. The valves
322A, 322B, 322C, 322D, and 322E, may be utilized to disengage the
precursor sources, purge gas source, and gas-phase sulfur precursor
sources from the reaction chamber 302, i.e., when the one of more
valves are in the closed position vapor produced by the sources may
be prevented from flowing into the reaction chamber 302.
[0096] The precursor delivery system 312 may further comprise flow
controllers 320A, 320B, 320C, 320D and 320E, configured for
monitoring and regulating the mass flow of the precursors and purge
gas into the reaction chamber 302. For example, the flow
controllers 320A, 320B, 320C, 320D, and 320E may comprise mass flow
controllers (MFCs).
[0097] One or more gas lines, such as gas lines 324, 326, 329, 330,
and 331, may be in fluid communication with both the
precursor/purge sources and the reaction chamber 302 to enable the
supply of vapors to the reaction chamber 302. In particular
embodiments, the precursor delivery system 312 may be in fluid
communication with a gas dispenser 332 configured for dispensing
precursor vapor and purge gas into the reaction chamber 302 and
over the substrate 304. As a non-limiting example, the gas
dispenser 332 may comprise a showerhead gas distribution mechanism
as illustrated in block form in FIG. 3. It should be noted that the
although shown in block form, the showerhead gas distribution
mechanism may be a relatively complex structure and may configured
for either mixing vapors from multiple sources, or maintaining a
separation between multiple vapors introduced into the showerhead
gas distribution mechanism. In addition, in exemplary embodiments,
the gas dispenser may comprise a showerhead gas distribution
mechanism configured to introduce the precursors into the reaction
chamber wherein the temperature of the showerhead gas distribution
mechanism is regulated below a temperature of 70.degree. C. Further
details regarding the temperature regulation of a showerhead gas
distribution mechanism may be found in U.S. application Ser. No.
15/636,307, filed on Jun. 28, 2017, titled "METHODS FOR DEPOSITING
A TRANSITION METAL NITRIDE FILM ON A SUBSTRATE BY ATOMIC LAYER
DEPOSITION AND RELATED DEPOSITION APPARATUS," all of which is
hereby incorporated by reference.
[0098] The exemplary semiconductor processing apparatus 300 may
also comprise a gas removal system constructed and arranged to
remove gases from the reaction chamber 302. For example, the
removal system may comprise an exhaust port 334 disposed within a
wall of the reaction chamber 302, an exhaust line 336 in fluid
communication with the exhaust port 334, and a vacuum pump in fluid
communication with the exhaust line 336 and configured for
evacuating gases from within the reaction chamber 302. Once the
gases have been exhausted from the reaction chamber 302 utilizing
the vacuum pump 338, they may be conveyed along additional exhaust
line 340 and exit the apparatus 300 where they may undergo further
abatement processes.
[0099] The exemplary semiconductor processing apparatus 300 may
further comprising a sequence controller 342 operably connected to
the precursor delivery system 312, the reaction chamber 302, and
the removal system by means of exemplary control lines 344A, 344B,
and 344C. The sequence controller 342 may comprise electronic
circuitry to selectively operate valves, heaters, flow controllers,
manifolds, pumps and other equipment associated with the
semiconductor processing apparatus 300. Such circuitry and
components operate to introduce precursor gases and purge gases
from sources 314A, 314B, 314C, 316, and 318. The sequence
controller 342 may also control the timing of precursor pulse
sequences, temperature of the substrate and reaction chamber, and
the pressure of the reaction chamber and various other operations
necessary to provide proper operation of the semiconductor
processing apparatus 300. The sequence controller 342 may also
comprise a memory 344 provided with a program to execute
semiconductor processes when run on the sequence controller 342.
For example, the sequence controller 342 may include modules such
as software or hardware components (e.g., FPGA or ASIC) which
perform certain semiconductor processes, such as, for example,
etching processes, cleaning processes, and/or particularly cyclical
deposition processes. A module can be configured to reside on an
addressable storage medium of the sequence controller 342 and may
be configured to execute one or semiconductor processes.
[0100] The example embodiments of the disclosure described above do
not limit the scope of the invention, since these embodiments are
merely examples of the embodiments of the invention, which is
defined by the appended claims and their legal equivalents. Any
equivalent embodiments are intended to be within the scope of this
invention. Indeed, various modifications of the disclosure, in
addition to those shown and described herein, such as alternative
useful combination of the elements described, may become apparent
to those skilled in the art from the description. Such
modifications and embodiments are also intended to fall within the
scope of the appended claims.
* * * * *